Phosphor

Claim 1

AN ELECTROLUMINESCENT LAMP HAVING FIRST AND SECOND SEPARATED ELECTRODES, AT LEAST ONE OF SAID ELECTRODES PERMITTING THE PASSAGE OF LIGHT THERETHROUGH, AND AN ELECTROLUMINESCENT PHOSPHOR INTERPOSED BETWEEN SAID ELECTRODES, SAID PHOSPHOR COMPRISING A BASE MATERIAL SELECTED FROM THE CLASS CONSISTING OF ZINC SULFIDE AND ZINC CADMIUM SULFIDE WHEREIN UP TO 20 MOLE PERCENT OF CADMIUM CAN BE SUBSTITUTED FOR AN EQUIVALENT MOLE PERCENT OF ZINC, SAID MATERIAL CONTAINING A COPPER ACTIVATOR AND AT LEAST ONE HALIDE COACTIVATOR SELECTED FROM THE CLASS CONSISTING OF CHLORIDE, BROMIDE AND IODIDE, THE ACTIVATOR AND COACTIVATOR CONCENTRATIONS BOTH FALLING WITHIN THE SAME APPROXIMATE RANGE OF 1X10-**4-5X10-**3 GRAM ATOMS PER MOLE OF BASE MATERIAL, SAID PHOSPHOR FURTHER CONTAINING AN ELEMENT SELECTED FROM THE GROUP CONSISTING OF COBALT AND NICKEL, THE NICKEL CONCENTRATION FALLING WITHIN THE APPROXIMATE RANGE 0.5X10-**4-1.0X**-3 GRAM ATOMS PER MOLE OF BASE MATERIAL, THE COBALT CONCENTRATION FALLING WITHIN THE APPROXIMATE RANGE OF 0.5X10**-5-1.0X10**-4 GRAM ATOMS PER MOLE OF BASE MATERIAL, AND MEANS TO APPLY AN ALTERNATING VOLTAGE BETWEEN SAID ELECTRODES, THE BRIGHTNESS WAVE OF THE LIGHT EMITTED BEING PRIMARILY COMPOSED OF THE TIME DEPENDENT COMPONENT, THE CONTINUOUS COMPONENT BEING ESSENTIALLY ABSENT.